Tunnel magnetoresistive effect element, magnetic memory, and built-in memory

A tunnel magnetoresistive effect element comprising:

• a magnetic tunnel junction;
• a side wall portion disposed on a side surface of the magnetic tunnel junction;
• a cap layer covering a top surface of the magnetic tunnel junction and a surface of the side wall portion;
• and
• an upper electrode layer disposed on the cap layer, the upper electrode layer including, as a metal chemical element, Al or Cu,
• wherein the cap layer includes an upper surface and a lower surface,
• the upper surface has a protruding shape that protrudes in a direction away from the magnetic tunnel junction in a first region which is positioned immediately above the top surface of the magnetic tunnel junction,
• the upper surface has a recess that can cause an electrical field concentration is recessed in a direction toward the side wall portion in a second region which is positioned immediately above the surface of the side wall portion,
• in the second region, the lower surface has a part in which a height of the lower surface is greater than the height of the lower surface in the first region,
• a height of the upper surface in the first region is greater than the height of the lower surface in the second region,
• the height between the lower surface of the first region and the upper surface of the first region is in a range of from 50 nm to 100 nm, and
• the cap layer includes a migration preventing layer extending from the first region to the second region, the migration preventing layer configured to prevent migration of the metal chemical element included in the upper electrode layer caused by a high electric field.